xStats are calculated using Statcast data in an attempt to make more objective observations of the game. Only the vertical and horizontal launch angles, exit velocities, batted ball distances, game time temperature, and ball park are taken into account. All other factors are ignored. The angle and exit velocity information is fed through an algorithm that lumps together similarly hit balls and finds their average success rates. Game time temperature and ball park information are used to adjust the exit velocities. You can read more about xStats in the Article section or on Rotographs.